The ash whitefly, Siphoninus phillyreae, was described as Aleyrodes phillyreae by Haliday (1835),
on Phillyrea latifolia collected in Dublin, Ireland. It has several synonyms listed in Mound and Halsey (1978).

In the United States, ash whitefly was first collected in Los Angeles County, California in 1988, and then spread to other counties. It was later discovered in Arizona, Nevada and New Mexico. It appeared in Raleigh, North Carolina in 1993. It is also reported from Arizona, Georgia, Nevada, New Mexico, South Carolina and Texas. A successful biological control program using a parasitic wasp reduced infestations to undetectable levels (western states) or possibly eliminated the infestion (North Carolina). In 2010, it was discovered in central (Lake Buena Vista) and northwestern (Panama City) Florida (Stocks and Hodges 2010).

Adult: The adult appears much like a typical whitefly with a light dusting of white wax. Depending on temperature, females live from 30 to 60 days, while males live an average of nine days. This rapid development time, without the presence of the parasitiod, initially produced numerous generations per year in California, whereas only two to three generations were reported in Egypt. Plus, the ability of all life stages to overwinter on non-deciduous hosts allows a rapid build-up in population at the start of the season (Stocks and Hodges 2010). Winged females lays eggs on the underside of the leaves. When the nymphs emerge, they rarely move far and feed on the plant sap until pupation (Gillespie 2000).

Pupa: On first observation, the pupal case appears similar to the white armor of a male snow scale. Closer observation with a hand lens reveals a whitefly pupal case with two longitudinal tufts of white wax. The vasiform orifice is surrounded by dark brown derma (inner, thicker layer of the cuticle), with the anal area appearing as a dark brown spot. Lateral areas of the pupal case are light beige. Depending on the age, lesser or greater amounts of white wax will be present. The dorsal surface has 40 to 50 long glassy tubercles similar to the cornicles found on aphids. These tubercular structures produce a droplet of glassy wax and this gives the pupal case an unusual appearance. The longitudinal white tufts of wax obscure some glassy tubercles (R.J. Gill, personal communication). The pupal case size is 0.8 to 1.0 mm long by 0.55 to 0.7 mm wide and is tan or beige in color(Mound 1966, Stocks and Hodges 2010).

Ash whitefly has the potential to become a serious pest in new environments. However, it has several natural enemies that can control its populations to under economic thresholds. These natural enemies include (Stocks and Hodges 2010):

The California Department of Food and Agriculture imported Encarsia sp. from Israel and Italy, and the coccinellid beetle Clitostethus arcuatus for the control of ash whitefly in California (Bellows et al. 1990). Encarsia inaron was discovered in the ash whitefly infestation in central Florida, while an unidentified parasitoid was associated with the infestation in northwestern Florida.

Mound LA. 1966. A revision of the British Aleyrodidae (Hemiptera: Homoptera). Bulletin of the British Museum of National History, Entomolgy 17: 419-420.

Mound LA, Halsey SH. 1978. Whitefly of the World. A Systematic Catalogue of the Aleyrodidae (Homoptera) with Host Plant and Natural Enemy Data. British Museum of Natural History) and John Wiley and Sons, New York, NY. pp. 192-193.